Field of the Disclosure
The present invention relates to an electromagnetic induction heat cooking apparatus, and more particularly to an induction heat cooking apparatus which includes a plurality of switching elements and a plurality of resonant circuits, and a method for driving the same.
Background
Generally, an induction heat cooking apparatus is an electric cooking apparatus in which a cooking function is performed in a method in which a high frequency current is caused to flow through a working coil or a heating coil, and an eddy current flows while a strong magnetic line of force generated thereby passes through a cooking container, and thus the cooking container itself is heated.
In the basic heating principle of the induction heat cooking apparatus, as the current is applied to the heating coil, the cooking container formed of a magnetic material generates heat due to induction heating, and the cooking container is heated by the heat it generates to perform cooking.
An inverter used in the induction heat cooking apparatus serves to switch a voltage applied to the heating coil so that the high frequency current flows through the heating coil. The inverter enables the high frequency current to flow through the heating coil by driving a switching element typically including an insulated gate bipolar transistor (IGBT), and thus a high frequency magnetic field is formed at the heating coil.
When two heating coils are provided at the induction heat cooking apparatus, two inverters including four switching elements are required to operate the two heating coils.
FIG. 1 is a view illustrating an induction heat cooking apparatus according to a related art.
FIG. 1 illustrates the induction heat cooking apparatus including two inverters and two heating coils.
Referring to FIG. 1, the induction heat cooking apparatus includes a rectifier 10, a first inverter 20, a second inverter 30, a first heating coil 40, a second heating coil 50, a first resonant capacitor 60 and a second resonant capacitor 70.
Each of the first and second inverters 20 and 30 includes two switching elements which switch input electric power and are connected in series, and the first and second heating coils 40 and 50 driven by an output voltage of the switch elements are connected to each connecting point of the switching elements connected in series. Other sides of the first and second heating coils 40 and 50 are connected to the resonant capacitors 60 and 70.
Driving of the switching elements is performed by a driving part. The switching elements apply a high frequency voltage to each of the heating coils, while being controlled by switching time output from the driving part and thus alternately operated. Since on/off time of each of the switching elements applied from the driving part is controlled with gradual compensation, the voltage supplied to each of the heating coils changes from a low voltage to a high voltage.
However, the induction heat cooking apparatus should include two inverter circuits including four switching elements to operate the two heating coils, and thus a volume of a product increases, and a price of the product also increases.
Further, when the number of heating coils is increased to three or more, a plurality of switching elements are required according to the number of heating coils.